AVX2

AVX2, or Advanced Vector Extensions 2, is an extension of the x86 AVX instruction set that broadens 256-bit SIMD (single instruction, multiple data) processing capabilities. Introduced by Intel in 2013 with the Haswell microarchitecture, it has been adopted on subsequent Intel generations and by many AMD processors. AVX2 expands 256-bit operations beyond floating-point to full integer arithmetic and logic, enabling efficient processing of large data sets in parallel. It supports 8 lanes of 32-bit integers or 4 lanes of 64-bit integers in a single instruction, among other enhancements.

Key features of AVX2 include expanded integer instruction support, enabling a wide range of 256-bit integer arithmetic and logical operations. It also adds memory-addressing improvements, notably gather and scatter instructions that load from or store to non-contiguous memory locations using index vectors. In addition, AVX2 provides enhanced data permutation, blending, and shuffling instructions to rearrange elements within 256-bit vectors more flexibly. These capabilities improve performance for workloads such as cryptography, data processing, graphics, and scientific computing where large-scale vectorization is beneficial.

Implementation and usage considerations: AVX2 relies on 256-bit YMM registers and uses the VEX-encoded instruction format, which helps with efficient encoding and execution. Software support comes from modern compilers and libraries, with typical enablement through compiler flags (for example, -mavx2). Not all workloads benefit equally; performance gains depend on data parallelism and memory bandwidth, and code may need to fall back to scalar paths on CPUs that do not support AVX2 or when vectors cannot be fully utilized.